Many digital logic circuits are implemented in complementary metal-oxide-semiconductors (CMOS). CMOS is a design style that uses both p-type and n-type (PMOS and NMOS) metal-oxide-semiconductor field effect transistors (MOSFETs) to create logic circuits used in electronic devices world-wide. CMOS technology is found in microprocessors, microcontrollers, semiconductor memory and many other digital logic integrated circuits (ICs). CMOS integrated circuits may be manufactured in great density and offer high operating speed, energy efficiency and a high degree of noise immunity relative to ICs based on bipolar transistors. For these reasons CMOS is a widely adopted technology in the field of electronic design.
As CMOS technology tends to become smaller, more dense and faster over time, improvements in high-speed processor design have outpaced those of certain semiconductor component integrated circuits, creating a bottleneck with respect to overall integrated circuit speed. One example of the bottleneck is a sense amplifier circuit where voltage transitions create long read and write cycle times, constraining the overall speed of a semiconductor memory integrated circuit. Memory circuits often use differential amplifiers in sense amplifier circuits because they offer certain advantages over sensing inverter circuits. Sensing inverter circuits are intrinsically slower when employing both a rising and falling transition in reading data. Differential amplifiers offer more flexibility, allowing integrated circuit designers to finely tune voltage differentials and power consumption to achieve desirable timing characteristics.
The same is true for many amplifier circuits where time is of the essence, which it almost always is. Single ended sensing amplifiers rely on detectable voltage transitions on an input line to trigger an output voltage. The voltage transitions constitute time delays, and therefore a bottleneck in the overall integrated circuit speed. Differential amplifiers overcome this by employing very small differential voltages to trigger an output voltage. The smaller voltage transitions take less time and speed up the sensing circuit. Improvements in differential amplifier application continue to develop in an effort to relieve the bottleneck in digital logic integrated circuits.